Automatic dispensers are being designed and used at gasoline stations and several such units are shown in U.S. Pat. Nos. 3,550,743; 3,605,973; 3,666,928; 3,731,777; 3,768,617; and 3,786,960. In these dispensers, a quantity of fuel is purchased by the customer, in terms of dollars or gallons or other units, and this purchase is registered in the dispenser, mechanically as by deposit of tokens or coins, or electrically as by a switch setting or electrical pulses. Typically the customer purchases tokens from an attendant and deposits them in the dispenser or pays the attendant and the attendant sets the register in the dispenser.
The customer then positions the hose nozzle in the fuel tank of the vehicle and opens the valve to start gasoline flow. When all of the fuel paid for is dispensed, the dispenser automatically shuts off gasoline flow. If for any reason the customer does not wish to take all the fuel paid for, the customer may shut off flow and return the hose nozzle to the dispenser. Change will automatically be paid to the customer for the value of the fuel paid for but not received.
Present day gasoline stations utilize a plurality of dispensers, typically 12, and it is desirable to be able to operate the 12 dispensers with a single attendant. In one mode of operation, the attendant runs from dispenser to dispenser as the customers drive in. This has not been satisfactory because one attendant cannot handle a busy location. In another mode of operation, customers pull up to the dispensers, take whatever amount of gasoline they desire, and then make payment to an attendant located at a control booth at the exit of the station, with the amount of fuel and the cost of the fuel being metered at the booth. This system has not been satisfactory in all respects, as it requires meter reading and change making by the attendant, a time consuming operation at a busy installation, and also has the problem of customers taking more fuel than they are prepared to pay for. Another form of remote operation utilizing non-change making dispensers is shown in U.S. Pat. No. 3,402,851. A more pertinent system with remote console and a plurality of change making dispensers is shown in the copending application Ser. No. 469,518, filed May 13, 1974 now U.S. Pat. No. 3,921,854 and assigned to the same assignee as the present application.
The system of the aforesaid copending application provides a bank of push button switches for selecting a dispenser and another bank of push button switches for selecting an amount to be dispensed. After the customer indicates the dispenser and amount and makes payment, the attendant actuates the console and enters the credits into the selected dispenser. If the customer changes his mind, or has made an error in stating the dispenser or amount, or if the attendant has made an incorrect entry, the selected dispenser can be reset. However the attendant has to make a manually written record of this change and this gives rise to problems in the record keeping.
It is an object of the present invention to provide a new and improved control unit for operation with a plurality of dispensers at a gasoline station providing for prepayment by the customer, control of the operation by a single attendant, automatic change payout to each customer when the amount of fuel paid for has not been taken, and the ability to remove credits from a selected dispenser (i.e., debit a dispenser) and automatically maintain a record of credits and debits. The invention will be described herein in conjunction with the dispenser of U.S. Pat. No. 3,605,973, but it will be readily understood that the invention is equally suitable for use with other change making dispensers. Also, while the invention is described as used with gasoline, it is equally suitable for dispensing of other fluid.